User-aware notification delivery

ABSTRACT

In one embodiment, a method includes one or more computing devices accessing a notification to be sent to a user, where the notification has a context. The method also includes one or more computing devices sending a request to a history service for historical notification data associated with the user with respect to the context of the notification and a ranking of the notification where the ranking indicates a probability of the user interacting with the notification. The method also includes one or more computing devices receiving the historical notification data and the ranking from the history service. Moreover, the method also includes one or more computing devices determining a notification policy to apply to the notification based at least in part on the context of the notification, the historical notification data, and the ranking. Furthermore, the method also includes one or more computing devices applying the notification policy to the notification to be sent to the user.

TECHNICAL FIELD

This disclosure generally relates to delivering notifications to a user.

BACKGROUND

A social-networking system, which may include a social-networkingwebsite, may enable its users (such as persons or organizations) tointeract with it and with each other through it. The social-networkingsystem may, with input from a user, create and store in thesocial-networking system a user profile associated with the user. Theuser profile may include demographic information, communication-channelinformation, and information on personal interests of the user. Thesocial-networking system may also, with input from a user, create andstore a record of relationships of the user with other users of thesocial-networking system, as well as provide services (e.g., wall posts,photo-sharing, event organization, messaging, games, or advertisements)to facilitate social interaction between or among users.

The social-networking system may send over one or more networks contentor messages related to its services to a mobile or other computingdevice of a user. A user may also install software applications on amobile or other computing device of the user for accessing a userprofile of the user and other data within the social-networking system.The social-networking system may generate a personalized set of contentobjects to display to a user, such as a newsfeed of aggregated storiesof other users connected to the user.

A mobile computing device—such as a smartphone, tablet computer, orlaptop computer—may include functionality for determining its location,direction, or orientation, such as a GPS receiver, compass, gyroscope,or accelerometer. Such a device may also include functionality forwireless communication, such as BLUETOOTH communication, near-fieldcommunication (NFC), or infrared (IR) communication or communicationwith a wireless local area networks (WLANs) or cellular-telephonenetwork. Such a device may also include one or more cameras, scanners,touchscreens, microphones, or speakers. Mobile computing devices mayalso execute software applications, such as games, web browsers, orsocial-networking applications. With social-networking applications,users may connect, communicate, and share information with other usersin their social networks.

SUMMARY OF PARTICULAR EMBODIMENTS

In particular embodiments, a notification system may delivernotifications to a user in a user-aware manner. Such notifications maybe sent through one or more delivery channels, e.g., sent by one or morecommunication media (e.g., SMS, MMS, email, application, voice) to oneor more unique endpoints (e.g., a telephone number, an email address, aparticular client device as specified by a unique device identifier). Inparticular embodiments, the notification system may utilize differenttechniques to attempt to provide a notification to a user in a mannerthat increases the likelihood that the user will interact with thenotification (e.g., a “click-through” action whereby the user clicks ona link presented in a visual notification presenting promotionalcontent, which then brings up a third-party website on the user'sscreen), which hopefully increases the likelihood that a “conversion”takes place—that the user takes some final action that is the ultimategoal of delivering the notification (e.g., completes an action, such asa registration, content consumption, or a purchase, on the third-partywebsite). In particular embodiments, elements of the notification systemmay be implemented as part of a social-networking system. In particularembodiments, elements of the notification system may be implemented aspart of a third-party system.

In particular embodiments, a policy engine of the notification systemmay assess a number of different factors in order to determine deliveryinstructions for a notification. For any particular notification, thepolicy engine may assess not only (1) information associated with thenotification (e.g., the source, the content, or the format) and (2)information associated with a particular user (e.g., demographicinformation for the user, the user's location, the user's availabledelivery channels and the status thereof, the user's current deliverycontext, user profile information, or social-networking information forthe user), but also (3) historical notification information about thisparticular user's responses to past notifications (e.g., conversionrates for different notification/context/delivery patterns) and aboutprior context/delivery patterns (if any) for the current notification(and interaction levels, if any, for those prior context/deliverypatterns).

The embodiments disclosed above are only examples, and the scope of thisdisclosure is not limited to them. Particular embodiments may includeall, some, or none of the components, elements, features, functions,operations, or steps of the embodiments disclosed above. Embodimentsaccording to the invention are in particular disclosed in the attachedclaims directed to a method, a storage medium, a system and a computerprogram product, wherein any feature mentioned in one claim category,e.g. method, can be claimed in another claim category, e.g. system, aswell. The dependencies or references back in the attached claims arechosen for formal reasons only. However any subject matter resultingfrom a deliberate reference back to any previous claims (in particularmultiple dependencies) can be claimed as well, so that any combinationof claims and the features thereof are disclosed and can be claimedregardless of the dependencies chosen in the attached claims. Thesubject-matter which can be claimed comprises not only the combinationsof features as set out in the attached claims but also any othercombination of features in the claims, wherein each feature mentioned inthe claims can be combined with any other feature or combination ofother features in the claims. Furthermore, any of the embodiments andfeatures described or depicted herein can be claimed in a separate claimand/or in any combination with any embodiment or feature described ordepicted herein or with any of the features of the attached claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates an example network environment associated with asocial-networking system.

FIG. 1B illustrates an example architecture for delivering notificationsto a user.

FIG. 2 illustrates an example social graph.

FIG. 3 illustrates an example embodiment of a notification system.

FIG. 4 illustrates an example method for handling notification deliveryin a user-aware manner.

FIG. 5 illustrates an example computer system.

DESCRIPTION OF EXAMPLE EMBODIMENTS

In particular embodiments, a notification system may delivernotifications to a user in a user-aware manner. Such notifications maybe sent through one or more delivery channels, e.g., sent by one or morecommunication media (e.g., SMS, MMS, email, application, voice) to oneor more unique endpoints (e.g., a telephone number, an email address, aparticular client device as specified by a unique device identifier). Inparticular embodiments, the notification system may utilize differenttechniques to attempt to provide a notification to a user in a mannerthat increases the likelihood that the user will interact with thenotification (e.g., a “click-through” action whereby the user clicks ona link presented in a visual notification presenting promotionalcontent, which then brings up a third-party website on the user'sscreen), which hopefully increases the likelihood that a “conversion”takes place—that the user takes some final action that is the ultimategoal of delivering the notification (e.g., completes an action, such asa registration, content consumption, or a purchase, on the third-partywebsite).

In particular embodiments, a policy engine of the notification systemmay assess a number of different factors in order to determine deliveryinstructions for a notification. For any particular notification, thepolicy engine may assess not only (1) information associated with thenotification (e.g., the source, the content, or the format) and (2)information associated with a particular user (e.g., demographicinformation for the user, the user's location, the user's availabledelivery channels and the status thereof, the user's current deliverycontext, user profile information, or social-networking information forthe user), but also (3) historical notification information about thisparticular user's responses to past notifications (e.g., conversionrates for different notification/context/delivery patterns) and aboutprior context/delivery patterns (if any) for the current notification(and interaction levels, if any, for those prior context/deliverypatterns).

In particular embodiments, a history service of the notification systemmay collect and analyze the user's responses to past notifications inorder to determine the user's level of interaction (if any) with thepast notifications. Information about the user's responses to pastnotifications may be stored in a historical notification data store. Thetype of historical data collected about a past notification may include,by way of example and not limitation: the notification content andformat, the source of the notification, the date and time when the pastnotification was delivered to the user, the delivery channel(s) to whichthe notification was sent, whether the notification was successfullydelivered to the delivery channel(s) (and attempted context/deliverypatterns), or information about a subsequent completed transaction(wherein the completed transaction is associated with the pastnotification), including time-to-completion.

Using such historical data, the history service may also rank, by theirconversion scores, different aspects of thenotification/context/delivery patterns for past notifications sent to aparticular user, such as, by way of example and not limitation: deliverychannels, notification content types, notification sources, deliverycontexts, or delivery patterns. In particular embodiments, the historyservice may compute the ranking of conversion scores by combiningtogether two sets of data, for example, the average conversion score fora particular delivery channel at a first time after delivery of thenotification (e.g., 3 hours after delivery) and the average conversionscore for a particular delivery channel at a second time after deliveryof the notification (e.g., 36 hours after delivery). Taking a globalview of such historical data, the history service may also rank, bytheir conversion scores, different aspects of thenotification/context/delivery patterns for past notifications across allusers.

As information about user interactions with notifications sent to theuser are sent back to the notification system, the history service maycontinuously update the historical notification data based on receivedinformation, so as to provide the policy engine with the most up-to-dateinformation about past user interactions. In some embodiments, thehistory service may also maintain a decision-tree model, based on thehistorical notification data, for determining delivery instructions fora current notification. The decision-tree model itself may be initiallyconstructed using a machine-learning algorithm, based on a set oftraining data and/or a pre-existing set of historical data.

In particular embodiments, a registration service of the notificationsystem may collect and store information sent by a device of the userupon enabling a new delivery channel (a communication medium-endpointcombination). For example, if the user installs a software applicationon their computing device through which notifications may be delivered,the application may send registration information back to theregistration service indicating that a new delivery channel is nowavailable for this particular user—that a new communication medium(e.g., the application) is available for a particular endpoint (e.g.,the computing device). Such registration information may be provided inthe form of a registration token identifying the user, the installedinstance, and the computing device. The registration information aboutthe user's available delivery channels may then be provided to thepolicy engine for use when determining the delivery policy to be appliedto a particular notification. Information about the user's availabledelivery channels may be stored in a registration data store. Theregistration data may include, by way of example and not limitation: aunique identifier for the endpoint, features and capabilities of theendpoint (e.g., audio-visual specifications, battery capacity, ornetwork connectivity specifications), a unique identifier for thecommunication medium, features and capabilities of the communicationmedium (e.g., maximum message size, data transfer allotment, or maximumbandwidth), or a unique identifier for the installed instance of thesoftware application.

By assessing information such as that described above, the policy enginemay generate a delivery policy for the notification. The delivery policymay provide instructions for a notification delivery service to deliverthe notification in accordance with a specified context/deliverypattern. The context/delivery pattern may provide instructions regardingwhen to send the notification (e.g., day, time, ideal delivery context),how to send the notification (e.g., which delivery channels should beutilized), a maximum duration beyond which the notification should bere-delivered, when and how to re-deliver the notification in the absenceof user interaction and/or successful conversion, or whether to deliverthe notification in light of (1) the information associated with thenotification, (2) the information associated with a particular user, and(3) the historical notification information.

Actual delivery of the notification may be handled by a notificationdelivery service, which receives the notification and the deliverypolicy. The notification delivery service may generate an appropriateform of the notification for delivery through the selected deliverychannel(s). The notification delivery service may schedule thenotification for delivery at a specified time and day, for delivery upondetecting a particular user delivery context (e.g., upon detecting thatthe user has begun actively using their mobile device; upon determining,based on the user's calendar information, that the user should beavailable; upon determining that the user's location has changed; orupon determining that the user has moved within a threshold proximity toone or more social-networking contacts of the user).

Information about user interactions with the notification may be sentback to a response-handling service by way of the same delivery channelby which the related notification was delivered. Such information mayinclude, for example, and without limitation: whether the user everactively opened the notification (including, e.g., how many times theuser actively opened the notification), user attention level withrespect to the opened notification (including, e.g., how many times theuser viewed or listened to the notification, how long the user paidattention on each occasion, and the user's delivery context on eachoccasion), whether the user clicked on a link in the notification, orwhether the user provided feedback regarding the notification (e.g.,clicking to “Like” or rate the notification, or commenting on thenotification). Such information may also factor in negative feedback,such as, for example, and without limitation: whether the user dismissedthe notification without opening it, whether the user subsequentlyblocked notifications from the source of the notification, whether theuser subsequently disabled push notifications, whether the usersubsequently logged out of the application, or whether the usersubsequently unsubscribed from receiving certain email notifications.Other factors may be considered when computing a conversion successrate, such as: comparison as against an expected level of interaction,comparison as against an average level of interaction, the duration oftime between delivery of the notification and the user interaction withthe notification, delivery patterns leading to the interaction, or thenumber and/or pattern of lower-level interactions leading up to ahigher-level interaction). A conversion success rate may be determinedbased on a target user interaction (e.g., in some cases, the ultimategoal of a notification may be to cause the user to open and view thefull text of the notification, whereas, in other cases, the ultimategoal of a notification may be to motivate the user to click on a link inthe notification and then complete a purchase, download, or registrationon a third-party website). The response-handling service may thenforward the user interaction information to the history service, whichmay collect and analyze the user's responses to past notifications, asdescribed above.

FIG. 1A illustrates an example network environment 100 associated with asocial-networking system. Network environment 100 includes a clientsystem 130, a social-networking system 160, and a third-party system 170connected to each other by a network 110. Although FIG. 1A illustrates aparticular arrangement of client system 130, social-networking system160, third-party system 170, and network 110, this disclosurecontemplates any suitable arrangement of client system 130,social-networking system 160, third-party system 170, and network 110.As an example and not by way of limitation, two or more of client system130, social-networking system 160, and third-party system 170 may beconnected to each other directly, bypassing network 110. As anotherexample, two or more of client system 130, social-networking system 160,and third-party system 170 may be physically or logically co-locatedwith each other in whole or in part. Moreover, although FIG. 1Aillustrates a particular number of client systems 130, social-networkingsystems 160, third-party systems 170, and networks 110, this disclosurecontemplates any suitable number of client systems 130,social-networking systems 160, third-party systems 170, and networks110. As an example and not by way of limitation, network environment 100may include multiple client system 130, social-networking systems 160,third-party systems 170, and networks 110.

This disclosure contemplates any suitable network 110. As an example andnot by way of limitation, one or more portions of network 110 mayinclude an ad hoc network, an intranet, an extranet, a virtual privatenetwork (VPN), a local area network (LAN), a wireless LAN (WLAN), a widearea network (WAN), a wireless WAN (WWAN), a metropolitan area network(MAN), a portion of the Internet, a portion of the Public SwitchedTelephone Network (PSTN), a cellular telephone network, or a combinationof two or more of these. Network 110 may include one or more networks110.

Links 150 may connect client system 130, social-networking system 160,and third-party system 170 to communication network 110 or to eachother. This disclosure contemplates any suitable links 150. Inparticular embodiments, one or more links 150 include one or morewireline (such as for example Digital Subscriber Line (DSL) or Data OverCable Service Interface Specification (DOCSIS)), wireless (such as forexample Wi-Fi or Worldwide Interoperability for Microwave Access(WiMAX)), or optical (such as for example Synchronous Optical Network(SONET) or Synchronous Digital Hierarchy (SDH)) links. In particularembodiments, one or more links 150 each include an ad hoc network, anintranet, an extranet, a VPN, a LAN, a WLAN, a WAN, a WWAN, a MAN, aportion of the Internet, a portion of the PSTN, a cellulartechnology-based network, a satellite communications technology-basednetwork, another link 150, or a combination of two or more such links150. Links 150 need not necessarily be the same throughout networkenvironment 100. One or more first links 150 may differ in one or morerespects from one or more second links 150.

In particular embodiments, client system 130 may be an electronic deviceincluding hardware, software, or embedded logic components or acombination of two or more such components and capable of carrying outthe appropriate functionalities implemented or supported by clientsystem 130. As an example and not by way of limitation, a client system130 may include a computer system such as a desktop computer, notebookor laptop computer, netbook, a tablet computer, e-book reader, GPSdevice, camera, personal digital assistant (PDA), handheld electronicdevice, cellular telephone, smartphone, other suitable electronicdevice, or any suitable combination thereof. This disclosurecontemplates any suitable client systems 130. A client system 130 mayenable a network user at client system 130 to access network 110. Aclient system 130 may enable its user to communicate with other users atother client systems 130.

In particular embodiments, client system 130 may include a web browser132, such as MICROSOFT INTERNET EXPLORER, GOOGLE CHROME or MOZILLAFIREFOX, and may have one or more add-ons, plug-ins, or otherextensions, such as TOOLBAR or YAHOO TOOLBAR. A user at client system130 may enter a Uniform Resource Locator (URL) or other addressdirecting the web browser 132 to a particular server (such as server162, or a server associated with a third-party system 170), and the webbrowser 132 may generate a Hyper Text Transfer Protocol (HTTP) requestand communicate the HTTP request to server. The server may accept theHTTP request and communicate to client system 130 one or more Hyper TextMarkup Language (HTML) files responsive to the HTTP request. Clientsystem 130 may render a webpage based on the HTML files from the serverfor presentation to the user. This disclosure contemplates any suitablewebpage files. As an example and not by way of limitation, webpages mayrender from HTML files, Extensible Hyper Text Markup Language (XHTML)files, or Extensible Markup Language (XML) files, according toparticular needs. Such pages may also execute scripts such as, forexample and without limitation, those written in JAVASCRIPT, JAVA,MICROSOFT SILVERLIGHT, combinations of markup language and scripts suchas AJAX (Asynchronous JAVASCRIPT and XML), and the like. Herein,reference to a webpage encompasses one or more corresponding webpagefiles (which a browser may use to render the webpage) and vice versa,where appropriate.

In particular embodiments, social-networking system 160 may be anetwork-addressable computing system that can host an online socialnetwork. Social-networking system 160 may generate, store, receive, andsend social-networking data, such as, for example, user-profile data,concept-profile data, social-graph information, or other suitable datarelated to the online social network. Social-networking system 160 maybe accessed by the other components of network environment 100 eitherdirectly or via network 110. As an example and not by way of limitation,client system 130 may access social-networking system 160 using a webbrowser 132, or a native application associated with social-networkingsystem 160 (e.g., a mobile social-networking application, a messagingapplication, another suitable application, or any combination thereof)either directly or via network 110. In particular embodiments,social-networking system 160 may include one or more servers 162. Eachserver 162 may be a unitary server or a distributed server spanningmultiple computers or multiple datacenters. Servers 162 may be ofvarious types, such as, for example and without limitation, web server,news server, mail server, message server, advertising server, fileserver, application server, exchange server, database server, proxyserver, another server suitable for performing functions or processesdescribed herein, or any combination thereof. In particular embodiments,each server 162 may include hardware, software, or embedded logiccomponents or a combination of two or more such components for carryingout the appropriate functionalities implemented or supported by server162. In particular embodiments, social-networking system 160 may includeone or more data stores 164. Data stores 164 may be used to storevarious types of information. In particular embodiments, the informationstored in data stores 164 may be organized according to specific datastructures. In particular embodiments, each data store 164 may be arelational, columnar, correlation, or other suitable database. Althoughthis disclosure describes or illustrates particular types of databases,this disclosure contemplates any suitable types of databases. Particularembodiments may provide interfaces that enable a client system 130, asocial-networking system 160, or a third-party system 170 to manage,retrieve, modify, add, or delete, the information stored in data store164.

In particular embodiments, social-networking system 160 may store one ormore social graphs in one or more data stores 164. In particularembodiments, a social graph may include multiple nodes—which may includemultiple user nodes (each corresponding to a particular user) ormultiple concept nodes (each corresponding to a particular concept)—andmultiple edges connecting the nodes. Social-networking system 160 mayprovide users of the online social network the ability to communicateand interact with other users. In particular embodiments, users may jointhe online social network via social-networking system 160 and then addconnections (e.g., relationships) to a number of other users ofsocial-networking system 160 to whom they want to be connected. Herein,the term “friend” may refer to any other user of social-networkingsystem 160 with whom a user has formed a connection, association, orrelationship via social-networking system 160.

In particular embodiments, social-networking system 160 may provideusers with the ability to take actions on various types of items orobjects, supported by social-networking system 160. As an example andnot by way of limitation, the items and objects may include groups orsocial networks to which users of social-networking system 160 maybelong, events or calendar entries in which a user might be interested,computer-based applications that a user may use, transactions that allowusers to buy or sell items via the service, interactions withadvertisements that a user may perform, or other suitable items orobjects. A user may interact with anything that is capable of beingrepresented in social-networking system 160 or by an external system ofthird-party system 170, which is separate from social-networking system160 and coupled to social-networking system 160 via a network 110.

In particular embodiments, social-networking system 160 may be capableof linking a variety of entities. As an example and not by way oflimitation, social-networking system 160 may enable users to interactwith each other as well as receive content from third-party systems 170or other entities, or to allow users to interact with these entitiesthrough an application programming interfaces (API) or othercommunication channels.

In particular embodiments, a third-party system 170 may include one ormore types of servers, one or more data stores, one or more interfaces,including but not limited to APIs, one or more web services, one or morecontent sources, one or more networks, or any other suitable components,e.g., that servers may communicate with. A third-party system 170 may beoperated by a different entity from an entity operatingsocial-networking system 160. In particular embodiments, however,social-networking system 160 and third-party systems 170 may operate inconjunction with each other to provide social-networking services tousers of social-networking system 160 or third-party systems 170. Inthis sense, social-networking system 160 may provide a platform, orbackbone, which other systems, such as third-party systems 170, may useto provide social-networking services and functionality to users acrossthe Internet.

In particular embodiments, a third-party system 170 may include athird-party content object provider. A third-party content objectprovider may include one or more sources of content objects, which maybe communicated to a client system 130. As an example and not by way oflimitation, content objects may include information regarding things oractivities of interest to the user, such as, for example, movie showtimes, movie reviews, restaurant reviews, restaurant menus, productinformation and reviews, or other suitable information. As anotherexample and not by way of limitation, content objects may includeincentive content objects, such as coupons, discount tickets, giftcertificates, or other suitable incentive objects.

In particular embodiments, social-networking system 160 also includesuser-generated content objects, which may enhance a user's interactionswith social-networking system 160. User-generated content may includeanything a user can add, upload, send, or “post” to social-networkingsystem 160. As an example and not by way of limitation, a usercommunicates posts to social-networking system 160 from a client system130. Posts may include data such as status updates or other textualdata, location information, photos, videos, links, music or othersimilar data or media. Content may also be added to social-networkingsystem 160 by a third-party through a “communication channel,” such as anewsfeed or stream.

In particular embodiments, social-networking system 160 may include avariety of servers, sub-systems, programs, modules, logs, and datastores. In particular embodiments, social-networking system 160 mayinclude one or more of the following: a web server, action logger,API-request server, relevance-and-ranking engine, content-objectclassifier, notification controller, action log,third-party-content-object-exposure log, inference module,authorization/privacy server, search module, advertisement-targetingmodule, user-interface module, user-profile store, connection store,third-party content store, or location store. Social-networking system160 may also include suitable components such as network interfaces,security mechanisms, load balancers, failover servers,management-and-network-operations consoles, other suitable components,or any suitable combination thereof. In particular embodiments,social-networking system 160 may include one or more user-profile storesfor storing user profiles. A user profile may include, for example,biographic information, demographic information, behavioral information,social information, or other types of descriptive information, such aswork experience, educational history, hobbies or preferences, interests,affinities, or location. Interest information may include interestsrelated to one or more categories. Categories may be general orspecific. As an example and not by way of limitation, if a user “likes”an article about a brand of shoes the category may be the brand, or thegeneral category of “shoes” or “clothing.” A connection store may beused for storing connection information about users. The connectioninformation may indicate users who have similar or common workexperience, group memberships, hobbies, educational history, or are inany way related or share common attributes. The connection informationmay also include user-defined connections between different users andcontent (both internal and external). A web server may be used forlinking social-networking system 160 to one or more client systems 130or one or more third-party system 170 via network 110. The web servermay include a mail server or other messaging functionality for receivingand routing messages between social-networking system 160 and one ormore client systems 130. An API-request server may allow a third-partysystem 170 to access information from social-networking system 160 bycalling one or more APIs. An action logger may be used to receivecommunications from a web server about a user's actions on or offsocial-networking system 160. In conjunction with the action log, athird-party-content-object log may be maintained of user exposures tothird-party-content objects. A notification controller may provideinformation regarding content objects to a client system 130.Information may be pushed to a client system 130 as notifications, orinformation may be pulled from client system 130 responsive to a requestreceived from client system 130. Authorization servers may be used toenforce one or more privacy settings of the users of social-networkingsystem 160. A privacy setting of a user determines how particularinformation associated with a user can be shared. The authorizationserver may allow users to opt in to or opt out of having their actionslogged by social-networking system 160 or shared with other systems(e.g., third-party system 170), such as, for example, by settingappropriate privacy settings. Third-party-content-object stores may beused to store content objects received from third parties, such as athird-party system 170. Location stores may be used for storing locationinformation received from client systems 130 associated with users.Advertisement-pricing modules may combine social information, thecurrent time, location information, or other suitable information toprovide relevant advertisements, in the form of notifications, to auser.

FIG. 1B illustrates an example architecture for delivering notificationsto a user (Alice Liddell). In one example embodiment described herein,elements of the notification system may be implemented as part of asocial-networking system, and the notification system may handledelivery of notifications generated by third-party systems as well as bythe social-networking system itself. In particular embodiments, elementsof the notification system may be implemented as part of a third-partysystem.

As shown in FIG. 1B, notifications may be delivered by way of a numberof different delivery channels 140. As discussed above, a deliverychannel 140 may comprise one or more uniquely-identified endpoint 142and one or more communication media 144. As shown in FIG. 1B,notifications may be delivered by one or more communication media (e.g.,SMS, MMS, email, application, voice, newsfeed, flag) to one or moreunique endpoints (e.g., a telephone number, an email address, aparticular client device as specified by a unique device identifier). Insome embodiments, a particular communication media may be able todeliver a notification to more than one endpoint—for example, athird-party application such as SNAPCHAT may be installed on the user'ssmartphone client device 130A and also on the user's laptop 130B.Communication media may be a push-type medium, such as SMS or email, orit may be a pull-type medium, such as newsfeed.

In particular embodiments, the notification system may select differentdelivery channels for notifications based on the user's availabledelivery channels and the status thereof. As discussed above, theinformation about the user's available delivery channels may beretrieved from the registration data store (e.g., information to enablethe notification system to deliver the notification to a SNAPCHATapplication). The notification system may also select different deliverychannels for notifications based on the user's current delivery context,which may include device status. For example, if Alice's smartphone iscurrently placed in Silent mode, and she just checked in at a movietheater with her friends, then delivery of any notifications may bedelayed until movement detected by the phone indicates that she isexiting the theater. The notification system may also choose to“escalate” a notification from a lower-ranked delivery channel (e.g.,newsfeed) to a higher-ranked delivery channel (e.g., SMS) whenre-delivering a notification, in order to increase the likelihood thatthe receiving user will interact with the notification. Further examplesand use cases are discussed herein with respect to FIG. 3.

FIG. 2 illustrates example social graph 200. In particular embodiments,social-networking system 160 may store one or more social graphs 200 inone or more data stores. In particular embodiments, social graph 200 mayinclude multiple nodes—which may include multiple user nodes 202 ormultiple concept nodes 204—and multiple edges 206 connecting the nodes.Example social graph 200 illustrated in FIG. 2 is shown, for didacticpurposes, in a two-dimensional visual map representation. In particularembodiments, a social-networking system 160, client system 130, orthird-party system 170 may access social graph 200 and relatedsocial-graph information for suitable applications. The nodes and edgesof social graph 200 may be stored as data objects, for example, in adata store (such as a social-graph database). Such a data store mayinclude one or more searchable or queryable indexes of nodes or edges ofsocial graph 200.

In particular embodiments, a user node 202 may correspond to a user ofsocial-networking system 160. As an example and not by way oflimitation, a user may be an individual (human user), an entity (e.g.,an enterprise, business, or third-party application), or a group (e.g.,of individuals or entities) that interacts or communicates with or oversocial-networking system 160. In particular embodiments, when a userregisters for an account with social-networking system 160,social-networking system 160 may create a user node 202 corresponding tothe user, and store the user node 202 in one or more data stores. Usersand user nodes 202 described herein may, where appropriate, refer toregistered users and user nodes 202 associated with registered users. Inaddition or as an alternative, users and user nodes 202 described hereinmay, where appropriate, refer to users that have not registered withsocial-networking system 160. In particular embodiments, a user node 202may be associated with information provided by a user or informationgathered by various systems, including social-networking system 160. Asan example and not by way of limitation, a user may provide his or hername, profile picture, contact information, birth date, sex, maritalstatus, family status, employment, education background, preferences,interests, or other demographic information. In particular embodiments,a user node 202 may be associated with one or more data objectscorresponding to information associated with a user. In particularembodiments, a user node 202 may correspond to one or more webpages.

In particular embodiments, a concept node 204 may correspond to aconcept. As an example and not by way of limitation, a concept maycorrespond to a place (such as, for example, a movie theater,restaurant, landmark, or city); a website (such as, for example, awebsite associated with social-network system 160 or a third-partywebsite associated with a web-application server); an entity (such as,for example, a person, business, group, sports team, or celebrity); aresource (such as, for example, an audio file, video file, digitalphoto, text file, structured document, or application) which may belocated within social-networking system 160 or on an external server,such as a web-application server; real or intellectual property (suchas, for example, a sculpture, painting, movie, game, song, idea,photograph, or written work); a game; an activity; an idea or theory;another suitable concept; or two or more such concepts. A concept node204 may be associated with information of a concept provided by a useror information gathered by various systems, including social-networkingsystem 160. As an example and not by way of limitation, information of aconcept may include a name or a title; one or more images (e.g., animage of the cover page of a book); a location (e.g., an address or ageographical location); a website (which may be associated with a URL);contact information (e.g., a phone number or an email address); othersuitable concept information; or any suitable combination of suchinformation. In particular embodiments, a concept node 204 may beassociated with one or more data objects corresponding to informationassociated with concept node 204. In particular embodiments, a conceptnode 204 may correspond to one or more webpages.

In particular embodiments, a node in social graph 200 may represent orbe represented by a webpage (which may be referred to as a “profilepage”). Profile pages may be hosted by or accessible tosocial-networking system 160. Profile pages may also be hosted onthird-party websites associated with a third-party server 170. As anexample and not by way of limitation, a profile page corresponding to aparticular external webpage may be the particular external webpage andthe profile page may correspond to a particular concept node 204.Profile pages may be viewable by all or a selected subset of otherusers. As an example and not by way of limitation, a user node 202 mayhave a corresponding user-profile page in which the corresponding usermay add content, make declarations, or otherwise express himself orherself. As another example and not by way of limitation, a concept node204 may have a corresponding concept-profile page in which one or moreusers may add content, make declarations, or express themselves,particularly in relation to the concept corresponding to concept node204.

In particular embodiments, a concept node 204 may represent athird-party webpage or resource hosted by a third-party system 170. Thethird-party webpage or resource may include, among other elements,content, a selectable or other icon, or other inter-actable object(which may be implemented, for example, in JavaScript, AJAX, or PHPcodes) representing an action or activity. As an example and not by wayof limitation, a third-party webpage may include a selectable icon suchas “like,” “check-in,” “eat,” “recommend,” or another suitable action oractivity. A user viewing the third-party webpage may perform an actionby selecting one of the icons (e.g., “check-in”), causing a clientsystem 130 to send to social-networking system 160 a message indicatingthe user's action. In response to the message, social-networking system160 may create an edge (e.g., a check-in-type edge) between a user node202 corresponding to the user and a concept node 204 corresponding tothe third-party webpage or resource and store edge 206 in one or moredata stores.

In particular embodiments, a pair of nodes in social graph 200 may beconnected to each other by one or more edges 206. An edge 206 connectinga pair of nodes may represent a relationship between the pair of nodes.In particular embodiments, an edge 206 may include or represent one ormore data objects or attributes corresponding to the relationshipbetween a pair of nodes. As an example and not by way of limitation, afirst user may indicate that a second user is a “friend” of the firstuser. In response to this indication, social-networking system 160 maysend a “friend request” to the second user. If the second user confirmsthe “friend request,” social-networking system 160 may create an edge206 connecting the first user's user node 202 to the second user's usernode 202 in social graph 200 and store edge 206 as social-graphinformation in one or more of data stores 164. In the example of FIG. 2,social graph 200 includes an edge 206 indicating a friend relationbetween user nodes 202 of user “A” and user “B” and an edge indicating afriend relation between user nodes 202 of user “C” and user “B.”Although this disclosure describes or illustrates particular edges 206with particular attributes connecting particular user nodes 202, thisdisclosure contemplates any suitable edges 206 with any suitableattributes connecting user nodes 202. As an example and not by way oflimitation, an edge 206 may represent a friendship, family relationship,business or employment relationship, fan relationship (including, e.g.,liking, etc.), follower relationship, visitor relationship (including,e.g., accessing, viewing, checking-in, sharing, etc.), subscriberrelationship, superior/subordinate relationship, reciprocalrelationship, non-reciprocal relationship, another suitable type ofrelationship, or two or more such relationships. Moreover, although thisdisclosure generally describes nodes as being connected, this disclosurealso describes users or concepts as being connected. Herein, referencesto users or concepts being connected may, where appropriate, refer tothe nodes corresponding to those users or concepts being connected insocial graph 200 by one or more edges 206.

In particular embodiments, an edge 206 between a user node 202 and aconcept node 204 may represent a particular action or activity performedby a user associated with user node 202 toward a concept associated witha concept node 204. As an example and not by way of limitation, asillustrated in FIG. 2, a user may “like,” “attended,” “played,”“listened,” “cooked,” “worked at,” or “watched” a concept, each of whichmay correspond to a edge type or subtype. A concept-profile pagecorresponding to a concept node 204 may include, for example, aselectable “check in” icon (such as, for example, a clickable “check in”icon) or a selectable “add to favorites” icon. Similarly, after a userclicks these icons, social-networking system 160 may create a “favorite”edge or a “check in” edge in response to a user's action correspondingto a respective action. As another example and not by way of limitation,a user (user “C”) may listen to a particular song (“Imagine”) using aparticular application (SPOTIFY, which is an online music application).In this case, social-networking system 160 may create a “listened” edge206 and a “used” edge (as illustrated in FIG. 2) between user nodes 202corresponding to the user and concept nodes 204 corresponding to thesong and application to indicate that the user listened to the song andused the application. Moreover, social-networking system 160 may createa “played” edge 206 (as illustrated in FIG. 2) between concept nodes 204corresponding to the song and the application to indicate that theparticular song was played by the particular application. In this case,“played” edge 206 corresponds to an action performed by an externalapplication (SPOTIFY) on an external audio file (the song “Imagine”).Although this disclosure describes particular edges 206 with particularattributes connecting user nodes 202 and concept nodes 204, thisdisclosure contemplates any suitable edges 206 with any suitableattributes connecting user nodes 202 and concept nodes 204. Moreover,although this disclosure describes edges between a user node 202 and aconcept node 204 representing a single relationship, this disclosurecontemplates edges between a user node 202 and a concept node 204representing one or more relationships. As an example and not by way oflimitation, an edge 206 may represent both that a user likes and hasused at a particular concept. Alternatively, another edge 206 mayrepresent each type of relationship (or multiples of a singlerelationship) between a user node 202 and a concept node 204 (asillustrated in FIG. 2 between user node 202 for user “E” and conceptnode 204 for “SPOTIFY”).

In particular embodiments, social-networking system 160 may create anedge 206 between a user node 202 and a concept node 204 in social graph200. As an example and not by way of limitation, a user viewing aconcept-profile page (such as, for example, by using a web browser or aspecial-purpose application hosted by the user's client system 130) mayindicate that he or she likes the concept represented by the conceptnode 204 by clicking or selecting a “Like” icon, which may cause theuser's client system 130 to send to social-networking system 160 amessage indicating the user's liking of the concept associated with theconcept-profile page. In response to the message, social-networkingsystem 160 may create an edge 206 between user node 202 associated withthe user and concept node 204, as illustrated by “like” edge 206 betweenthe user and concept node 204. In particular embodiments,social-networking system 160 may store an edge 206 in one or more datastores. In particular embodiments, an edge 206 may be automaticallyformed by social-networking system 160 in response to a particular useraction. As an example and not by way of limitation, if a first useruploads a picture, watches a movie, or listens to a song, an edge 206may be formed between user node 202 corresponding to the first user andconcept nodes 204 corresponding to those concepts. Although thisdisclosure describes forming particular edges 206 in particular manners,this disclosure contemplates forming any suitable edges 206 in anysuitable manner.

In particular embodiments, an advertisement may be text (which may beHTML-linked), one or more images (which may be HTML-linked), one or morevideos, audio, one or more ADOBE FLASH files, a suitable combination ofthese, or any other suitable advertisement in any suitable digitalformat presented on one or more web pages, in one or more e-mails, or inconnection with search results requested by a user. In addition or as analternative, an advertisement may be one or more sponsored stories(e.g., a news-feed or ticker item on social-networking system 160). Asponsored story may be a social action by a user (such as “liking” apage, “liking” or commenting on a post on a page, RSVPing to an eventassociated with a page, voting on a question posted on a page, checkingin to a place, using an application or playing a game, or “liking” orsharing a website) that an advertiser promotes, for example, by havingthe social action presented within a pre-determined area of a profilepage of a user or other page, presented with additional informationassociated with the advertiser, bumped up or otherwise highlightedwithin news feeds or tickers of other users, or otherwise promoted. Theadvertiser may pay to have the social action promoted. The social actionmay be promoted within or on social-networking system 160. In additionor as an alternative, the social action may be promoted outside or offof social-networking system 160, where appropriate. In particularembodiments, a page may be an on-line presence (such as a webpage orwebsite within or outside of social-networking system 160) of abusiness, organization, or brand facilitating its sharing of stories andconnecting with people. A page may be customized, for example, by addingapplications, posting stories, or hosting events.

A sponsored story may be generated from stories in users' news feeds andpromoted to specific areas within displays of users' web browsers whenviewing a web page associated with social-networking system 160.Sponsored stories are more likely to be viewed by users, at least inpart because sponsored stories generally involve interactions orsuggestions by the users' friends, fan pages, or other connections. Inconnection with sponsored stories, particular embodiments may utilizeone or more systems, components, elements, functions, methods,operations, or steps disclosed in U.S. patent application Ser. No.13/327,557, entitled “Sponsored Stories Unit Creation from OrganicActivity Stream” and filed 15 Dec. 2011, U.S. Patent ApplicationPublication No. 2012/0203831, entitled “Sponsored Stories Unit Creationfrom Organic Activity Stream” and filed 3 Feb. 2012 as U.S. patentapplication Ser. No. 13/020,745, or U.S. Patent Application PublicationNo. 2012/0233009, entitled “Endorsement Subscriptions for SponsoredStories” and filed 9 Mar. 2011 as U.S. patent application Ser. No.13/044,506, which are all incorporated herein by reference as an exampleand not by way of limitation. In particular embodiments, sponsoredstories may utilize computer-vision algorithms to detect products inuploaded images or photos lacking an explicit connection to anadvertiser as disclosed in U.S. patent application Ser. No. 13/212,356,entitled “Computer-Vision Content Detection for Sponsored Stories” andfiled 18 Aug. 2011, which is incorporated herein by reference as anexample and not by way of limitation.

As described above, an advertisement may be text (which may beHTML-linked), one or more images (which may be HTML-linked), one or morevideos, audio, one or more ADOBE FLASH files, a suitable combination ofthese, or any other suitable advertisement in any suitable digitalformat. In particular embodiments, an advertisement may be requested fordisplay within third-party webpages, social-networking-system webpages,or other pages. An advertisement may be displayed in a dedicated portionof a page, such as in a banner area at the top of the page, in a columnat the side of the page, in a GUI of the page, in a pop-up window, overthe top of content of the page, or elsewhere with respect to the page.In addition or as an alternative, an advertisement may be displayedwithin an application or within a game. An advertisement may bedisplayed within dedicated pages, requiring the user to interact with orwatch the advertisement before the user may access a page, utilize anapplication, or play a game. The user may, for example view theadvertisement through a web browser.

A user may interact with an advertisement in any suitable manner. Theuser may click or otherwise select the advertisement, and theadvertisement may direct the user (or a browser or other applicationbeing used by the user) to a page associated with the advertisement. Atthe page associated with the advertisement, the user may take additionalactions, such as purchasing a product or service associated with theadvertisement, receiving information associated with the advertisement,or subscribing to a newsletter associated with the advertisement. Anadvertisement with audio or video may be played by selecting a componentof the advertisement (like a “play button”). In particular embodiments,an advertisement may include one or more games, which a user or otherapplication may play in connection with the advertisement. Anadvertisement may include functionality for responding to a poll orquestion in the advertisement.

An advertisement may include social-networking-system functionality thata user may interact with. For example, an advertisement may enable auser to “like” or otherwise endorse the advertisement by selecting anicon or link associated with endorsement. Similarly, a user may sharethe advertisement with another user (e.g., through social-networkingsystem 160) or RSVP (e.g., through social-networking system 160) to anevent associated with the advertisement. In addition or as analternative, an advertisement may include social-networking-systemcontent directed to the user. For example, an advertisement may displayinformation about a friend of the user within social-networking system160 who has taken an action associated with the subject matter of theadvertisement.

Social-networking-system functionality or content may be associated withan advertisement in any suitable manner. For example, an advertisingsystem (which may include hardware, software, or both for receiving bidsfor advertisements and selecting advertisements in response) mayretrieve social-networking functionality or content fromsocial-networking system 160 and incorporate the retrievedsocial-networking functionality or content into the advertisement beforeserving the advertisement to a user. Examples of selecting and providingsocial-networking-system functionality or content with an advertisementare disclosed in U.S. Patent Application Publication No. 2012/0084160,entitled “Providing Social Endorsements with Online Advertising” andfiled 5 Oct. 2010 as U.S. patent application Ser. No. 12/898,662, and inU.S. Patent Application Publication No. 2012/0232998, entitled“Selecting Social Endorsement Information for an Advertisement forDisplay to a Viewing User” and filed 8 Mar. 2011 as U.S. patentapplication Ser. No. 13/043,424, which are both incorporated herein byreference as examples only and not by way of limitation. Interactingwith an advertisement that is associated with social-networking-systemfunctionality or content may cause information about the interaction tobe displayed in a profile page of the user in social-networking-system160.

Particular embodiments may facilitate the delivery of advertisements tousers that are more likely to find the advertisements more relevant oruseful. For example, an advertiser may realize higher conversion rates(and therefore higher return on investment (ROI) from advertising) byidentifying and targeting users that are more likely to find itsadvertisements more relevant or useful. The advertiser may useuser-profile information in social-networking system 160 to identifythose users. In addition or as an alternative, social-networking system160 may use user-profile information in social-networking system 160 toidentify those users for the advertiser. As examples and not by way oflimitation, particular embodiments may target users with the following:invitations or suggestions of events; suggestions regarding coupons,deals, or wish-list items; suggestions regarding friends' life events;suggestions regarding groups; advertisements; or social advertisements.Such targeting may occur, where appropriate, on or withinsocial-networking system 160, off or outside of social-networking system160, or on mobile computing devices of users. When on or withinsocial-networking system 160, such targeting may be directed to users'news feeds, search results, e-mail or other in-boxes, or notificationschannels or may appear in particular area of web pages ofsocial-networking system 160, such as a right-hand side of a web page ina concierge or grouper area (which may group along a right-hand railadvertisements associated with the same concept, node, or object) or anetwork-ego area (which may be based on what a user is viewing on theweb page and a current news feed of the user). When off or outside ofsocial-networking system 160, such targeting may be provided through athird-party website, e.g., involving an ad exchange or a social plug-in.When on a mobile computing device of a user, such targeting may beprovided through push notifications to the mobile computing device.

Targeting criteria used to identify and target users may includeexplicit, stated user interests on social-networking system 160 orexplicit connections of a user to a node, object, entity, brand, or pageon social-networking system 160. In addition or as an alternative, suchtargeting criteria may include implicit or inferred user interests orconnections (which may include analyzing a user's history, demographic,social or other activities, friends' social or other activities,subscriptions, or any of the preceding of other users similar to theuser (based, e.g., on shared interests, connections, or events)).Particular embodiments may utilize platform targeting, which may involveplatform and “like” impression data; contextual signals (e.g., “Who isviewing now or has viewed recently the page for COCA-COLA?”);light-weight connections (e.g., “check-ins”); connection lookalikes;fans; extracted keywords; EMU advertising; inferential advertising;coefficients, affinities, or other social-graph information;friends-of-friends connections; pinning or boosting; deals; polls;household income, social clusters or groups; products detected in imagesor other media; social- or open-graph edge types; geo-prediction; viewsof profile or pages; status updates or other user posts (analysis ofwhich may involve natural-language processing or keyword extraction);events information; or collaborative filtering. Identifying andtargeting users may also include privacy settings (such as useropt-outs), data hashing, or data anonymization, as appropriate.

To target users with advertisements, particular embodiments may utilizeone or more systems, components, elements, functions, methods,operations, or steps disclosed in the following, which are allincorporated herein by reference as examples and not by way oflimitation: U.S. Patent Application Publication No. 2009/0119167,entitled “Social Advertisements and Other Informational Messages on aSocial Networking Website and Advertising Model for Same” and filed 18Aug. 2008 as U.S. patent application Ser. No. 12/193,702; U.S. PatentApplication Publication No. 2009/0070219, entitled “TargetingAdvertisements in a Social Network” and filed 20 Aug. 2008 as U.S.patent application Ser. No. 12/195,321; U.S. Patent ApplicationPublication No. 2012/0158501, entitled “Targeting Social Advertising toFriends of Users Who Have Interacted With an Object Associated with theAdvertising” and filed 15 Dec. 2010 as U.S. patent application Ser. No.12/968,786; or U.S. Patent Application Publication No. 2012/0166532,entitled “Contextually Relevant Affinity Prediction in aSocial-Networking System” and filed 23 Dec. 2010 as U.S. patentapplication Ser. No. 12/978,265.

An advertisement may be presented or otherwise delivered using plug-insfor web browsers or other applications, iframe elements, news feeds,tickers, notifications (which may include, for example, e-mail, ShortMessage Service (SMS) messages, or notifications), or other means. Anadvertisement may be presented or otherwise delivered to a user on amobile or other computing device of the user. In connection withdelivering advertisements, particular embodiments may utilize one ormore systems, components, elements, functions, methods, operations, orsteps disclosed in the following, which are all incorporated herein byreference as examples and not by way of limitation: U.S. PatentApplication Publication No. 2012/0159635, entitled “Comment Plug-In forThird-Party System” and filed 15 Dec. 2010 as U.S. patent applicationSer. No. 12/969,368; U.S. Patent Application Publication No.2012/0158753, entitled “Comment Ordering System” and filed 15 Dec. 2010as U.S. patent application Ser. No. 12/969,408; U.S. Pat. No. 7,669,123,entitled “Dynamically Providing a News Feed About a User of a SocialNetwork” and filed 11 Aug. 2006 as U.S. patent application Ser. No.11/503,242; U.S. Pat. No. 8,402,094, entitled “Providing a NewsfeedBased on User Affinity for Entities and Monitored Actions in a SocialNetwork Environment” and filed 11 Aug. 2006 as U.S. patent applicationSer. No. 11/503,093; U.S. Patent Application Publication No.2012/0072428, entitled “Action Clustering for News Feeds” and filed 16Sep. 2010 as U.S. patent application Ser. No. 12/884,010; U.S. PatentApplication Publication No. 2011/0004692, entitled “GatheringInformation about Connections in a Social Networking Service” and filed1 Jul. 2009 as U.S. patent application Ser. No. 12/496,606; U.S. PatentApplication Publication No. 2008/0065701, entitled “Method and Systemfor Tracking Changes to User Content in an Online Social Network” andfiled 12 Sep. 2006 as U.S. patent application Ser. No. 11/531,154; U.S.Patent Application Publication No. 2008/0065604, entitled “FeedingUpdates to Landing Pages of Users of an Online Social Network fromExternal Sources” and filed 17 Jan. 2007 as U.S. patent application Ser.No. 11/624,088; U.S. Pat. No. 8,244,848, entitled “IntegratedSocial-Network Environment” and filed 19 Apr. 2010 as U.S. patentapplication Ser. No. 12/763,171; U.S. Patent Application Publication No.2011/0083101, entitled “Sharing of Location-Based Content Item inSocial-Networking Service” and filed 6 Oct. 2009 as U.S. patentapplication Ser. No. 12/574,614; U.S. Pat. No. 8,150,844, entitled“Location Ranking Using Social-Graph Information” and filed 18 Aug. 2010as U.S. patent application Ser. No. 12/858,718; U.S. patent applicationSer. No. 13/051,286, entitled “Sending Notifications to Users Based onUsers' Notification Tolerance Levels” and filed 18 Mar. 2011; U.S.patent application Ser. No. 13/096,184, entitled “Managing NotificationsPushed to User Devices” and filed 28 Apr. 2011; U.S. patent applicationSer. No. 13/276,248, entitled “Platform-Specific Notification DeliveryChannel” and filed 18 Oct. 2011; or U.S. Patent Application PublicationNo. 2012/0197709, entitled “Mobile Advertisement with Social Componentfor Geo-Social Networking System” and filed 1 Feb. 2011 as U.S. patentapplication Ser. No. 13/019,061. Although this disclosure describes orillustrates particular advertisements being delivered in particular waysand in connection with particular content, this disclosure contemplatesany suitable advertisements delivered in any suitable ways and inconnection with any suitable content.

In particular embodiments, social-networking system 160 may determinethe social-graph affinity (which may be referred to herein as“affinity”) of various social-graph entities for each other. Affinitymay represent the strength of a relationship or level of interestbetween particular objects associated with the online social network,such as users, concepts, content, actions, advertisements, other objectsassociated with the online social network, or any suitable combinationthereof. Affinity may also be determined with respect to objectsassociated with third-party systems 170 or other suitable systems. Anoverall affinity for a social-graph entity for each user, subjectmatter, or type of content may be established. The overall affinity maychange based on continued monitoring of the actions or relationshipsassociated with the social-graph entity. Although this disclosuredescribes determining particular affinities in a particular manner, thisdisclosure contemplates determining any suitable affinities in anysuitable manner.

In particular embodiments, social-networking system 160 may measure orquantify social-graph affinity using an affinity coefficient (which maybe referred to herein as “coefficient”). The coefficient may representor quantify the strength of a relationship between particular objectsassociated with the online social network. The coefficient may alsorepresent a probability or function that measures a predictedprobability that a user will perform a particular action based on theuser's interest in the action. In this way, a user's future actions maybe predicted based on the user's prior actions, where the coefficientmay be calculated at least in part a the history of the user's actions.Coefficients may be used to predict any number of actions, which may bewithin or outside of the online social network. As an example and not byway of limitation, these actions may include various types ofcommunications, such as sending messages, posting content, or commentingon content; various types of a observation actions, such as accessing orviewing profile pages, media, or other suitable content; various typesof coincidence information about two or more social-graph entities, suchas being in the same group, tagged in the same photograph, checked-in atthe same location, or attending the same event; or other suitableactions. Although this disclosure describes measuring affinity in aparticular manner, this disclosure contemplates measuring affinity inany suitable manner.

In particular embodiments, social-networking system 160 may use avariety of factors to calculate a coefficient. These factors mayinclude, for example, user actions, types of relationships betweenobjects, location information, other suitable factors, or anycombination thereof. In particular embodiments, different factors may beweighted differently when calculating the coefficient. The weights foreach factor may be static or the weights may change according to, forexample, the user, the type of relationship, the type of action, theuser's location, and so forth. Ratings for the factors may be combinedaccording to their weights to determine an overall coefficient for theuser. As an example and not by way of limitation, particular useractions may be assigned both a rating and a weight while a relationshipassociated with the particular user action is assigned a rating and acorrelating weight (e.g., so the weights total 100%). To calculate thecoefficient of a user towards a particular object, the rating assignedto the user's actions may comprise, for example, 60% of the overallcoefficient, while the relationship between the user and the object maycomprise 40% of the overall coefficient. In particular embodiments, thesocial-networking system 160 may consider a variety of variables whendetermining weights for various factors used to calculate a coefficient,such as, for example, the time since information was accessed, decayfactors, frequency of access, relationship to information orrelationship to the object about which information was accessed,relationship to social-graph entities connected to the object, short- orlong-term averages of user actions, user feedback, other suitablevariables, or any combination thereof. As an example and not by way oflimitation, a coefficient may include a decay factor that causes thestrength of the signal provided by particular actions to decay withtime, such that more recent actions are more relevant when calculatingthe coefficient. The ratings and weights may be continuously updatedbased on continued tracking of the actions upon which the coefficient isbased. Any type of process or algorithm may be employed for assigning,combining, averaging, and so forth the ratings for each factor and theweights assigned to the factors. In particular embodiments,social-networking system 160 may determine coefficients usingmachine-learning algorithms trained on historical actions and past userresponses, or data farmed from users by exposing them to various optionsand measuring responses. Although this disclosure describes calculatingcoefficients in a particular manner, this disclosure contemplatescalculating coefficients in any suitable manner.

In particular embodiments, social-networking system 160 may calculate acoefficient based on a user's actions. Social-networking system 160 maymonitor such actions on the online social network, on a third-partysystem 170, on other suitable systems, or any combination thereof. Anysuitable type of user actions may be tracked or monitored. Typical useractions include viewing profile pages, creating or posting content,interacting with content, tagging or being tagged in images, joininggroups, listing and confirming attendance at events, checking-in atlocations, liking particular pages, creating pages, and performing othertasks that facilitate social action. In particular embodiments,social-networking system 160 may calculate a coefficient based on theuser's actions with particular types of content. The content may beassociated with the online social network, a third-party system 170, oranother suitable system. The content may include users, profile pages,posts, news stories, headlines, instant messages, chat roomconversations, emails, advertisements, pictures, video, music, othersuitable objects, or any combination thereof. Social-networking system160 may analyze a user's actions to determine whether one or more of theactions indicate an affinity for subject matter, content, other users,and so forth. As an example and not by way of limitation, if a user maymake frequently posts content related to “coffee” or variants thereof,social-networking system 160 may determine the user has a highcoefficient with respect to the concept “coffee”. Particular actions ortypes of actions may be assigned a higher weight and/or rating thanother actions, which may affect the overall calculated coefficient. Asan example and not by way of limitation, if a first user emails a seconduser, the weight or the rating for the action may be higher than if thefirst user simply views the user-profile page for the second user.

In particular embodiments, social-networking system 160 may calculate acoefficient based on the type of relationship between particularobjects. Referencing the social graph 200, social-networking system 160may analyze the number and/or type of edges 206 connecting particularuser nodes 202 and concept nodes 204 when calculating a coefficient. Asan example and not by way of limitation, user nodes 202 that areconnected by a spouse-type edge (representing that the two users aremarried) may be assigned a higher coefficient than user nodes 202 thatare connected by a friend-type edge. In other words, depending upon theweights assigned to the actions and relationships for the particularuser, the overall affinity may be determined to be higher for contentabout the user's spouse than for content about the user's friend. Inparticular embodiments, the relationships a user has with another objectmay affect the weights and/or the ratings of the user's actions withrespect to calculating the coefficient for that object. As an exampleand not by way of limitation, if a user is tagged in first photo, butmerely likes a second photo, social-networking system 160 may determinethat the user has a higher coefficient with respect to the first photothan the second photo because having a tagged-in-type relationship withcontent may be assigned a higher weight and/or rating than having alike-type relationship with content. In particular embodiments,social-networking system 160 may calculate a coefficient for a firstuser based on the relationship one or more second users have with aparticular object. In other words, the connections and coefficientsother users have with an object may affect the first user's coefficientfor the object. As an example and not by way of limitation, if a firstuser is connected to or has a high coefficient for one or more secondusers, and those second users are connected to or have a highcoefficient for a particular object, social-networking system 160 maydetermine that the first user should also have a relatively highcoefficient for the particular object. In particular embodiments, thecoefficient may be based on the degree of separation between particularobjects. The lower coefficient may represent the decreasing likelihoodthat the first user will share an interest in content objects of theuser that is indirectly connected to the first user in the social graph200. As an example and not by way of limitation, social-graph entitiesthat are closer in the social graph 200 (i.e., fewer degrees ofseparation) may have a higher coefficient than entities that are furtherapart in the social graph 200.

In particular embodiments, social-networking system 160 may calculate acoefficient based on location information. Objects that aregeographically closer to each other may be considered to be more relatedor of more interest to each other than more distant objects. Inparticular embodiments, the coefficient of a user towards a particularobject may be based on the proximity of the object's location to acurrent location associated with the user (or the location of a clientsystem 130 of the user). A first user may be more interested in otherusers or concepts that are closer to the first user. As an example andnot by way of limitation, if a user is one mile from an airport and twomiles from a gas station, social-networking system 160 may determinethat the user has a higher coefficient for the airport than the gasstation based on the proximity of the airport to the user.

In particular embodiments, social-networking system 160 may performparticular actions with respect to a user based on coefficientinformation. Coefficients may be used to predict whether a user willperform a particular action based on the user's interest in the action.A coefficient may be used when generating or presenting any type ofobjects to a user, such as advertisements, search results, news stories,media, messages, notifications, or other suitable objects. Thecoefficient may also be utilized to rank and order such objects, asappropriate. In this way, social-networking system 160 may provideinformation that is relevant to user's interests and currentcircumstances, increasing the likelihood that they will find suchinformation of interest. In particular embodiments, social-networkingsystem 160 may generate content based on coefficient information.Content objects may be provided or selected based on coefficientsspecific to a user. As an example and not by way of limitation, thecoefficient may be used to generate media for the user, where the usermay be presented with media for which the user has a high overallcoefficient with respect to the media object. As another example and notby way of limitation, the coefficient may be used to generateadvertisements for the user, where the user may be presented withadvertisements for which the user has a high overall coefficient withrespect to the advertised object. In particular embodiments,social-networking system 160 may generate search results based oncoefficient information. Search results for a particular user may bescored or ranked based on the coefficient associated with the searchresults with respect to the querying user. As an example and not by wayof limitation, search results corresponding to objects with highercoefficients may be ranked higher on a search-results page than resultscorresponding to objects having lower coefficients.

In particular embodiments, social-networking system 160 may calculate acoefficient in response to a request for a coefficient from a particularsystem or process. To predict the likely actions a user may take (or maybe the subject of) in a given situation, any process may request acalculated coefficient for a user. The request may also include a set ofweights to use for various factors used to calculate the coefficient.This request may come from a process running on the online socialnetwork, from a third-party system 170 (e.g., via an API or othercommunication channel), or from another suitable system. In response tothe request, social-networking system 160 may calculate the coefficient(or access the coefficient information if it has previously beencalculated and stored). In particular embodiments, social-networkingsystem 160 may measure an affinity with respect to a particular process.Different processes (both internal and external to the online socialnetwork) may request a coefficient for a particular object or set ofobjects. Social-networking system 160 may provide a measure of affinitythat is relevant to the particular process that requested the measure ofaffinity. In this way, each process receives a measure of affinity thatis tailored for the different context in which the process will use themeasure of affinity.

In connection with social-graph affinity and affinity coefficients,particular embodiments may utilize one or more systems, components,elements, functions, methods, operations, or steps disclosed in U.S.patent application Ser. No. 11/503,093, filed 11 Aug. 2006, U.S. patentapplication Ser. No. 12/977,027, filed 22 Dec. 2010, U.S. patentapplication Ser. No. 12/978,265, filed 23 Dec. 2010, and U.S. patentapplication Ser. No. 13/632,869, filed 1 Oct. 2012, each of which isincorporated by reference.

In particular embodiments, one or more of the content objects of theonline social network may be associated with a privacy setting. Theprivacy settings (or “access settings”) for an object may be stored inany suitable manner, such as, for example, in association with theobject, in an index on an authorization server, in another suitablemanner, or any combination thereof. A privacy setting of an object mayspecify how the object (or particular information associated with anobject) can be accessed (e.g., viewed or shared) using the online socialnetwork. Where the privacy settings for an object allow a particularuser to access that object, the object may be described as being“visible” with respect to that user. As an example and not by way oflimitation, a user of the online social network may specify privacysettings for a user-profile page identify a set of users that may accessthe work experience information on the user-profile page, thus excludingother users from accessing the information. In particular embodiments,the privacy settings may specify a “blocked list” of users that shouldnot be allowed to access certain information associated with the object.In other words, the blocked list may specify one or more users orentities for which an object is not visible. As an example and not byway of limitation, a user may specify a set of users that may not accessphotos albums associated with the user, thus excluding those users fromaccessing the photo albums (while also possibly allowing certain usersnot within the set of users to access the photo albums). In particularembodiments, privacy settings may be associated with particularsocial-graph elements. Privacy settings of a social-graph element, suchas a node or an edge, may specify how the social-graph element,information associated with the social-graph element, or content objectsassociated with the social-graph element can be accessed using theonline social network. As an example and not by way of limitation, aparticular concept node 204 corresponding to a particular photo may havea privacy setting specifying that the photo may only be accessed byusers tagged in the photo and their friends. In particular embodiments,privacy settings may allow users to opt in or opt out of having theiractions logged by social-networking system 160 or shared with othersystems (e.g., third-party system 170). In particular embodiments, theprivacy settings associated with an object may specify any suitablegranularity of permitted access or denial of access. As an example andnot by way of limitation, access or denial of access may be specifiedfor particular users (e.g., only me, my roommates, and my boss), userswithin a particular degrees-of-separation (e.g., friends, orfriends-of-friends), user groups (e.g., the gaming club, my family),user networks (e.g., employees of particular employers, students oralumni of particular university), all users (“public”), no users(“private”), users of third-party systems 170, particular applications(e.g., third-party applications, external websites), other suitableusers or entities, or any combination thereof. Although this disclosuredescribes using particular privacy settings in a particular manner, thisdisclosure contemplates using any suitable privacy settings in anysuitable manner.

In particular embodiments, one or more servers 162 may beauthorization/privacy servers for enforcing privacy settings. Inresponse to a request from a user (or other entity) for a particularobject stored in a data store 164, social-networking system 160 may senda request to the data store 164 for the object. The request may identifythe user associated with the request and may only be sent to the user(or a client system 130 of the user) if the authorization serverdetermines that the user is authorized to access the object based on theprivacy settings associated with the object. If the requesting user isnot authorized to access the object, the authorization server mayprevent the requested object from being retrieved from the data store164, or may prevent the requested object from be sent to the user. Inthe search query context, an object may only be generated as a searchresult if the querying user is authorized to access the object. In otherwords, the object must have a visibility that is visible to the queryinguser. If the object has a visibility that is not visible to the user,the object may be excluded from the search results. Although thisdisclosure describes enforcing privacy settings in a particular manner,this disclosure contemplates enforcing privacy settings in any suitablemanner.

FIG. 3 illustrates an example embodiment of a notification system 320. Anotification provider 310 may provide notifications 312 for delivery.Notification provider 310 may include the social-networking system or athird-party system. In the example embodiment illustrated in FIG. 3,notifications 312 may all be targeted to the same user, yet delivereddifferently, due to differences in the current context, the user'ssocial-networking information relating to the content of thenotification, the user's past history of interacting with notificationssent by a particular source, etc. In particular embodiments, policyengine 322 of notification system 320 may assess information associatedwith the notification (e.g., the source, the content, or the format).Such information may be provided within the content of notifications 312or as associated metadata.

In particular embodiments, the policy engine 322 may also assessinformation associated with a particular user (e.g., demographicinformation for the user, the user's location, the user's availabledelivery channels 140 and the status thereof, the user's currentdelivery context, user profile information, or social-networkinginformation for the user). The policy engine 322 may retrieveinformation about the user's available delivery channels 140 fromregistration data store 332. Information such as the demographicinformation for the user, user profile information, or social-networkinginformation for the user may be retrieved as user data 334 and socialdata 338. Information about the user's current delivery context may beretrieved as context data 336—this category of information may cover anyaspect of the user's current delivery context, such as, by way ofexample and not limitation: information about: a location of the user, acalendar associated with the user, an indicated status of the user, ascheduled event associated with the location, a trajectory of the user,a device status of one or more client devices associated with the user,or the user's current location with respect to other users to whom theuser is connected in their social network.

In particular embodiments, policy engine 322 may also retrievehistorical notification information about this particular user'sresponses to past notifications (e.g., conversion rates for differentnotification/context/delivery patterns) and about prior context/deliverypatterns (if any) for the current notification (and interaction levels,if any, for those prior context/delivery patterns) from history service324. Once policy engine 322 has considered the relevant factors andproduced a policy to be applied to notifications 312, notificationdelivery service 340 may handle formatting and delivering thenotification in accordance with the context/delivery pattern specifiedin the delivery policy.

Notification delivery service 340 may generate an appropriate form ofthe notification for delivery through a delivery channel 140, based onthe features and capabilities of the underlying medium and endpoint. Thenotification delivery service may schedule the notification for deliveryat a specified time and day, for delivery upon detecting a particularuser delivery context (e.g., upon detecting that the user has begunactively using their mobile device; upon determining, based on theuser's calendar information, that the user should be available; upondetermining that the user's location has changed; or upon determiningthat the user has moved within a threshold proximity to one or moresocial-networking contacts of the user).

After having delivered the notifications to delivery channels 140, userinteraction data 314 may be sent back to an interaction handling service350, which sends the user interaction data 314 on to history service324. History service 324 of the notification system may collect andanalyze the user's responses to past notifications in order to determinethe user's level of interaction (if any) with the past notifications.Information about the user's responses to past notifications may bestored in historical notification data store 330.

FIG. 4 illustrates an example method for handling notification deliveryin a user-aware manner. In step 410, the notification system receives anotification to be delivered. For example, a social-networking messagemay be sent from user Alice's designated best friend on thesocial-networking system to Alice.

In step 420, the notification system determines information about thenotification, such as (1) information associated with the notification(e.g., the source, the content, or the format) and (2) informationassociated with a particular user (e.g., demographic information for theuser, the user's location, the user's available delivery channels andthe status thereof, the user's current delivery context, user profileinformation, or social-networking information for the user). In thissituation, the message may include buzzwords such as “hospital” and“accident.” In addition, the message may be sent at 2:40 AM on a Sundaymorning, and may include the name of a friend who is a first degreefriend on Alice's social network. The message may also include the nameof the hospital that the first degree friend is currently located at.

By retrieving information about Alice's current delivery context, thepolicy engine may determine that (1) the hospital is within 20 milesaway from her based on a determination of her current location; (2) thatshe was actively using her mobile device 15 minutes prior to her bestfriend sending the message by the social-networking system; (3) that shetypically goes to bed after 2:30 AM on Sunday mornings based on herhistorical activity, including pictures and posts uploaded to thesocial-networking website; (4) that she typically will place her phoneface down on a surface prior to going to sleep (e.g., as determined by aminimum 4 hour period of inactivity of her mobile device). Based on herrecent activity, historical activity, the current time being 2:40 AM,and the determination that Alice has not placed her phone face down on asurface, the policy engine may conclude that she is likely still awake(and likely to interact with the notification).

By retrieving social-networking information about Alice, the policyengine may determine that Alice, her best friend, and the first degreefriend all went to high school together and live in the sameneighborhood based on: her profile information and location information,her best friend's profile information and location information, thefirst degree friend's profile information and location information, andAlice's, best friend's and first degree friend's posts on thesocial-networking website. The policy engine may also determine thatAlice, her designated best friend, and the first degree friend have abunch scheduled for 11:00 AM that Sunday morning based on Alice's recentposts on the social-networking website. Thus, the policy engine maydetermine that Alice is very close with the first degree friend as well,and thus is more likely to respond to the message.

In step 430, the notification system retrieves historical notificationdata and ranking scores from the history service. The policy engine mayalso determine that Alice typically responds to messages sent by herdesignated best friend within an average of 2 minutes regardless of whenthe messages are sent to her based at least in part on her previousmessaging data. In addition, the policy engine may determine that shetypically responds to messages send after midnight within an average of5 minutes. Thus, the policy engine may conclude that she typicallyresponds to late night messages very quickly, and is very likely torespond to a message from her designated best friend. In addition, thepolicy engine may determine that she typically responds to messages sentto her mobile device on average within 10 minutes, messages sent to herlaptop computer on average within 2 hours, emails to her mobile deviceand/or laptop computer on average within 30 minutes (and in particular,emails sent to her mobile device on average within 10 minutes), andvoicemails to her mobile device within 3 hours. Thus, the policy enginemay determine that she is more likely to respond to SMS messages andemails sent to her mobile device than any other endpoint.

In step 440, the notification system determines a notification policy,which is applied to the notification in step 450. In particularembodiments, certain notification types (e.g., invitations toparticipate in a game) may be sent to certain delivery channels (e.g.,newsfeed page) but never to certain other delivery channels (e.g., SMSto her cellphone). Given the nature of the communication, thenotification policy may indicate that an SMS message should be re-sentto her mobile device once every five minutes until she interacts withthe notification or dismisses it. In particular embodiments, thenotification policy may also indicate that a voice call should be madeto her mobile device (using an automated voice) in order to leave Alicea voicemail and/or to give her an opportunity to pick up the phone andto be connected to her best friend's cellphone.

Based on these determinations, the policy engine may determine thatgiven the urgency and importance of the request, Alice is highly likelyto interact with the notification of the message and to act upon thecontent of the notification of the message. Therefore, given the highlevel of importance of the notification, the delivery context of thenotification, and the historical data, the notification policy indicatesthat the message is to be immediately delivered by all available mediato all endpoints (as in step 460). In particular embodiments, once Alicehas responded in one delivery channel to a notification sent by multipledelivery channels, any unopened notifications sent to other deliverychannels may be recalled or retracted.

In step 470, the notification system receives information about userinteractions with the notification, and then updates the historicalnotification data and the conversion score rankings in step 480. Asdiscussed in our example, once Alice views the text message and/orlistens to the voicemail, information about that user interaction willbe sent back to the notification system, so that the notification systemis aware that it should not send the same message through the samedelivery channel.

In a second example, an event invitation message may be received from acoordinator of an invitation-only dinner club group to all members ofthe dinner club group (step 410). In this situation, the dinner clubgroup may be a paid membership group, of which Alice is a member. Themessage may indicate that La Folie is having a special classic Provençalcuisine tasting event this Saturday with guest chef Joël Robuchon, thatthe event includes a 12-course tasting menu and costs $350/person, andthat space is limited to the first 25 people who RSVP on a first come,first served, basis.

In step 420, the notification system may determine a number of factorspertaining to her delivery context. The notification system maydetermine that La Folie is within 35 miles from her home location. Thenotification system may also determine that Alice likely owns a carbased on determining that user's workplace is about 25 miles from herhome location and that she is not located close to public transportationand does not usually take public transportation, which may be determinedbased on her location data. In addition, the notification system maydetermine that she posted a request for information on recommendationsfor local auto repair shops on the social-networking website threemonths ago. Thus, the notification system may determine that she owns acar, and that the 35 mile distance is a reasonable travel distance forher.

The notification system may determine that Alice is currently on abusiness trip in a city that is 2000 miles away from her home locationbased on location data and her activity on the social-networking website(e.g., she posted on the social-networking website that she will be inChicago for a business trip for the week and inviting friends in thearea out for dinner). The notification system may also determine thatshe is scheduled to fly back home on Friday based on her calendar andher conversations with other users on the social-networking website.Thus, the notification system may determine that although she is notcurrently within a reasonable travel distance given her current locationdetermined by the social-networking system, she will be within areasonable travel distance on the day of the special tasting event andthus will not immediately dismiss the message based on unavailability.

The notification system may also determine that Alice loves French foodbased at least in part on her social-networking profile, herfood-related posts and pictures, her comments on other user's posts andpictures on French food, and her frequented restaurants. In particular,the notification system may determine that she has been to all Frenchrestaurants within a 60 mile radius of her home location, dines out onaverage three times a week for dinner, and goes to a French restaurantat least once a week for dinner, based at least in part on informationcollect on her location during dinnertime during the week, her posts andpictures on the social-networking system, and her credit cardtransaction information. In addition, the notification system maydetermine that whenever she travels for work, she always schedulesreservations for at least one French restaurant in the area around thetravel location based at least in part on her calendar information,posts and pictures uploaded to her social-networking website, and creditcard transactions. Thus, the notification system may determine that shemay be very interested in the special tasting event, and thus verylikely to interact with the notification of such an event.

In step 430, the notification system retrieves historical notificationdata and ranking scores from the history service. The notificationsystem may determine that Alice is typically very responsive to messagessent from the dinner club group, and at least views all messages sent bythe dinner club group within an average of 3 minutes after receiving themessage based at least in part on her social-networking activity andgeneral mobile device activity. As an example, and not by way oflimitation, the notification system may determine that she is viewingthe messages based on her interaction with the instant messenger, mail,and/or voicemail application, including opening the messenger and/ormail application, and 30 seconds to a minute of inactivity on the device(which the notification system determines to be the user viewing themessage) or pressing a play button for a voicemail message. In addition,the notification system determines that she clicks on content presentedin the messages at least 85% of the time, and when the content relatesto French food, she clicks on content presented in the messages 100% ofthe time. Thus, the notification system may determine that she is verylikely to interact with the notification of the special tasting eventwith 3-5 minutes after sending the message.

Furthermore, the notification system may determine that Alice iscurrently within a movie theatre based on location information, and hasbeen at the movie theatre for two hours based on tracking and locationinformation. In addition, the notification system may determine that shehas her mobile device on silent mode, and that the mobile device is facedown on a surface, based on location information, mobile devicegyroscope information, and mobile device settings information. Thus, thenotification system may determine that she will likely not respond toany messages sent immediately at this time. However, the notificationsystem may determine that the movie will likely end in 20 minutes basedon local movie-times data. In addition, the notification system maydetermine that, based on historical use data, she always checks his/hermobile device immediately after leaving a movie theatre. Thus, thenotification system may determine that she will much more likely checktheir mobile device and interact with notifications after 20 minutes.

In step 440, based on these determinations, the notification system maydetermine that there is a very high likelihood that Alice will interactwith the notification of the message from the coordinator of a dinnerclub group and act upon the content of the notification of the specialtasting event, and that this notification is urgent given the timelimitations associated with the content. Therefore, given the highranking of the notification, the context of the notification, and thehistorical data, the notification policy indicates that the messageshould be delivered to the user by all available delivery channels.However, in step 450 and 460, because she is unlikely to view thenotification at the current time based on her current activities, thepolicy may include delaying the sending of the notification to her forat least 20 minutes so that she will receive the notification after themovie has likely ended and thus will be more likely to immediatelyinteract with the notification and act on the content of thenotification. Once information indicating that the user viewed the SMSmessage is received (in step 470), any as-of-yet unopened emails may berecalled.

In a third example, in step 410, the notification system may receive apromotional message may be sent to a predetermined number of users(e.g., a message broadcast to a predetermined group of users) notifyingthem of a MAXMARA closeout sale at a particular store location where allitems are 40-70% off starting this Friday, and where the message is tobe sent out this Wednesday.

In step 420, the notification system may determine that Alice visitsthat MAXMARA store once every week based on her location information,and usually remains at the store for at least an hour during each visit.Thus, the notification system may determine that she likes MAXMARAclothing, and would be interested in any sales going on at MAXMARA. Inaddition, the notification system may determine that even though shevisits the MAXMARA store once a week, she only buys clothes from thatstore once a month based on her location information, her posts and/orpictures uploaded to the social-networking website, and her credit cardinformation. In addition, the notification system may determine that sheonly buys clothing at MAXMARA once a month in part because of the highprices for the clothing. The notification system may determine thatMAXMARA rarely has sales based on information from MAXMARA's website,local advertisements, and store information. Thus, the notificationsystem concludes that she may be very interested in the closeout sale,and therefore the notification should be sent to her as soon as possibledue to the limited duration of time until the sale.

In step 430, the notification system may determine that Alice rarelyclicks on emails associated with advertisements based on her interactionwith their email notifications. In particular, the notification systemmay determine that she only views and clicks through links and contentpresented in email notifications no more than 5% of the time. Inaddition, the notification system may determine that she receives onaverage 10 advertisement ads per hour based on a determination of theamount and type of email content she receives. Thus, the notificationsystem may determine that emailing notifications to her may not be avery effective method to get her to interact with the notification andact upon the content of the notification. However, due to the urgency ofthe notification, the notification system may determine a time duringthe day that she may be most likely to check emails and viewnotifications. For example, the notification system may determine thatshe likes to browse the internet and briefly glance through the mostrecent 20 or so emails based on social-networking webpage activity and3rd party application data (e.g., an email application linked to hersocial-networking webpage). In addition, the notification system maydetermine that she usually likes to go to bed between 11:00-11:30 PMduring the weekdays, and around 12:30 AM on the weekends, based onsocial-networking webpage activity, location data, mobile device dataincluding usage of the device and interaction with certain applications(e.g., an alarm clock application). Thus, the notification system maydetermine that given her limited interaction with advertisementnotifications by email, the most effective method of getting her tointeract with the notification sent by email is to send the notificationto her around 11:00 PM during the weekdays and around 12:00 AM on theweekends. In addition, the notification system may determine that Aliceinteracts with SMS messages including advertisements about 50% of thetime, and clicks through links to content associated with theadvertisement around 30% of the time. Thus, the notification system maydetermine that SMS messaging is another viable option to sendnotifications to her, but also may not have a high chance of userinteraction.

The notification system may also determine that Alice has a big holidayparty coming up on the calendar in two weeks based at least in part onher calendar information, social-networking activity (e.g., heracceptance of a social-networking invitation regarding the party, hercomments or discussions with other users relating to the holiday party),email information, and recent internet and/or in-store shoppingactivity. In addition, the notification system may determine that shehas previously purchased a nice dress at an upscale store prior to thebig holiday party each year based on her social-networking information(e.g., previous posts or pictures of the dress on her social-networkingwebpage), location information, and credit card information. Thus, thenotification system may determine that she may be shopping at upscalestores for dresses, and thus is more likely to visit MAXMARA also to doshopping. Thus, the notification system may determine that she may bevery interested in the closeout sale at MAXMARA.

Based on these determinations, the notification system may determinethat that Alice is very likely to interact with the notification of theMAXMARA sale and act upon the content of the notification of themessage. Therefore, in step 440, given the urgency of the request, andgiven the high ranking of the notification, the context of thenotification, and the historical data, the policy for sending her thenotification may be to immediately send the notification to hertelephone number via SMS but to wait until specified times to send thenotification to her email address (e.g., 11:30 PM on weekdays and 12:30AM on weekends) for maximum effectiveness of the notifications. In step470, once the notification system receives an indication that Aliceviewed the SMS message and clicked on the link to go to MAXMARA'swebpage about the sale, the notification system may refrain from sendingher the emails if she immediately makes a purchase.

In a fourth example, in step 410, the notification system may receive apromotional notification to be sent to a large group of users (e.g., amessage broadcast to a predetermined group of shoppers) notifying themof a 10% off coupon at Bloomingdales for all women's coats and shoes.

In step 420, the notification system may determine that Alice oftenvisits Stanford Mall, but does not typically visit Bloomingdales when atStanford Mall based at least in part on her location information, hersocial-networking check-ins and posts, and her credit card information.In addition, the notification system may determine that it is nowFebruary in Palo Alto and that the weather has been in the high 70's inthe past 3 weeks based at least in part on calendar information, localweather information, her location data, and her social-networkingwebpage data (e.g., her posts of how nice the weather has been, whatkinds of shoes and clothes she has been wearing, etc.). Thus, thenotification system may conclude that she may not be particularlyinterested in Bloomingdale's coupon for women's coats and shoes, andthus there may be low probability that she will interact with anotification including a Bloomingdale's coupon.

In addition, the notification system may determine that she is onvacation in Hawaii, and will be returning after the sale will be overbased on her calendar information, location information,social-networking webpage information (e.g., posting pictures and/orupdates of where she has been in Hawaii), and other social mediainformation (e.g., information from TWITTER). In addition, in step 430,the notification system may determine that she rarely clicks on couponsof any kind from any vendor, based on her previously interactions ofignoring and/or actively deleting/blocking advertising notifications onher mobile device, and such information is determined based at least inpart on the social-networking system's and the 3rd party system's dataon her previous responses to advertisements. Thus, the notificationsystem may conclude that it is highly unlikely that she will interactwith the notification comprising the 10% off coupon from Bloomingdales.

Based on these determinations, the notification system may determinethat there is a very low likelihood that Alice will interact with thenotification comprising the coupon from Bloomingdales at all, and a verylow likelihood that she will act upon the content of the notification.Therefore, given the lower ranking of the notification, the context ofthe notification, and the historical data, the notification systemdetermines that no particular strategy will be helpful in increasing thelikelihood of her interacting with the notification. In fact, based onthe historical data, in step 440, the notification system may determinethat she will generally ignore these notifications, and in some cases,will actively block some of these notifications relating to advertising(step 450). Thus, the policy for delivering this notification to her maybe to simply send the message to her in the least distracting method(e.g., by displaying it only once in a newsfeed when she is logged intoa social-networking application) and to not use any other media or sendto any other endpoints associated with this user.

However, if (in step 470), information is received that Alice did infact click on the link and purchase gift-wrapped children's clothing tobe shipped to her brother's address, in step 480, the notificationsystem may update the historical notification data and ranking scoreswith this new information.

Particular embodiments may repeat one or more steps of the method ofFIG. 4, where appropriate. Although this disclosure describes andillustrates particular steps of the method of FIG. 4 as occurring in aparticular order, this disclosure contemplates any suitable steps of themethod of FIG. 4 occurring in any suitable order. Moreover, althoughthis disclosure describes and illustrates an example method for methodfor handling notification delivery in a user-aware manner including theparticular steps of the method of FIG. 4, this disclosure contemplatesany suitable method for method for handling notification delivery in auser-aware manner including any suitable steps, which may include all,some, or none of the steps of the method of FIG. 4, where appropriate.Furthermore, although this disclosure describes and illustratesparticular components, devices, or systems carrying out particular stepsof the method of FIG. 4, this disclosure contemplates any suitablecombination of any suitable components, devices, or systems carrying outany suitable steps of the method of FIG. 4.

In particular embodiments, the social-networking system may sendnotifications to increase the likelihood that the user will view certainstories that the user appears to have overlooked in their newsfeed. Suchnotifications may be sent only when a combined score based on the user'saffinity with the story and the likely conversion score exceeds aparticular threshold. In some embodiments, the social-networking systemmay periodically check whether the user has viewed a particular story,update the combined score for the story, then determine whether thenotification should be sent (e.g., when the updated combined scoreexceeds threshold).

FIG. 5 illustrates an example computer system 500. In particularembodiments, one or more computer systems 500 perform one or more stepsof one or more methods described or illustrated herein. In particularembodiments, one or more computer systems 500 provide functionalitydescribed or illustrated herein. In particular embodiments, softwarerunning on one or more computer systems 500 performs one or more stepsof one or more methods described or illustrated herein or providesfunctionality described or illustrated herein. Particular embodimentsinclude one or more portions of one or more computer systems 500.Herein, reference to a computer system may encompass a computing device,and vice versa, where appropriate. Moreover, reference to a computersystem may encompass one or more computer systems, where appropriate.

This disclosure contemplates any suitable number of computer systems500. This disclosure contemplates computer system 500 taking anysuitable physical form. As example and not by way of limitation,computer system 500 may be an embedded computer system, a system-on-chip(SOC), a single-board computer system (SBC) (such as, for example, acomputer-on-module (COM) or system-on-module (SOM)), a desktop computersystem, a laptop or notebook computer system, an interactive kiosk, amainframe, a mesh of computer systems, a mobile telephone, a personaldigital assistant (PDA), a server, a tablet computer system, or acombination of two or more of these. Where appropriate, computer system500 may include one or more computer systems 500; be unitary ordistributed; span multiple locations; span multiple machines; spanmultiple data centers; or reside in a cloud, which may include one ormore cloud components in one or more networks. Where appropriate, one ormore computer systems 500 may perform without substantial spatial ortemporal limitation one or more steps of one or more methods describedor illustrated herein. As an example and not by way of limitation, oneor more computer systems 500 may perform in real time or in batch modeone or more steps of one or more methods described or illustratedherein. One or more computer systems 500 may perform at different timesor at different locations one or more steps of one or more methodsdescribed or illustrated herein, where appropriate.

In particular embodiments, computer system 500 includes a processor 502,memory 504, storage 506, an input/output (I/O) interface 508, acommunication interface 510, and a bus 512. Although this disclosuredescribes and illustrates a particular computer system having aparticular number of particular components in a particular arrangement,this disclosure contemplates any suitable computer system having anysuitable number of any suitable components in any suitable arrangement.

In particular embodiments, processor 502 includes hardware for executinginstructions, such as those making up a computer program. As an exampleand not by way of limitation, to execute instructions, processor 502 mayretrieve (or fetch) the instructions from an internal register, aninternal cache, memory 504, or storage 506; decode and execute them; andthen write one or more results to an internal register, an internalcache, memory 504, or storage 506. In particular embodiments, processor502 may include one or more internal caches for data, instructions, oraddresses. This disclosure contemplates processor 502 including anysuitable number of any suitable internal caches, where appropriate. Asan example and not by way of limitation, processor 502 may include oneor more instruction caches, one or more data caches, and one or moretranslation lookaside buffers (TLBs). Instructions in the instructioncaches may be copies of instructions in memory 504 or storage 506, andthe instruction caches may speed up retrieval of those instructions byprocessor 502. Data in the data caches may be copies of data in memory504 or storage 506 for instructions executing at processor 502 tooperate on; the results of previous instructions executed at processor502 for access by subsequent instructions executing at processor 502 orfor writing to memory 504 or storage 506; or other suitable data. Thedata caches may speed up read or write operations by processor 502. TheTLBs may speed up virtual-address translation for processor 502. Inparticular embodiments, processor 502 may include one or more internalregisters for data, instructions, or addresses. This disclosurecontemplates processor 502 including any suitable number of any suitableinternal registers, where appropriate. Where appropriate, processor 502may include one or more arithmetic logic units (ALUs); be a multi-coreprocessor; or include one or more processors 502. Although thisdisclosure describes and illustrates a particular processor, thisdisclosure contemplates any suitable processor.

In particular embodiments, memory 504 includes main memory for storinginstructions for processor 502 to execute or data for processor 502 tooperate on. As an example and not by way of limitation, computer system500 may load instructions from storage 506 or another source (such as,for example, another computer system 500) to memory 504. Processor 502may then load the instructions from memory 504 to an internal registeror internal cache. To execute the instructions, processor 502 mayretrieve the instructions from the internal register or internal cacheand decode them. During or after execution of the instructions,processor 502 may write one or more results (which may be intermediateor final results) to the internal register or internal cache. Processor502 may then write one or more of those results to memory 504. Inparticular embodiments, processor 502 executes only instructions in oneor more internal registers or internal caches or in memory 504 (asopposed to storage 506 or elsewhere) and operates only on data in one ormore internal registers or internal caches or in memory 504 (as opposedto storage 506 or elsewhere). One or more memory buses (which may eachinclude an address bus and a data bus) may couple processor 502 tomemory 504. Bus 512 may include one or more memory buses, as describedbelow. In particular embodiments, one or more memory management units(MMUs) reside between processor 502 and memory 504 and facilitateaccesses to memory 504 requested by processor 502. In particularembodiments, memory 504 includes random access memory (RAM). This RAMmay be volatile memory, where appropriate Where appropriate, this RAMmay be dynamic RAM (DRAM) or static RAM (SRAM). Moreover, whereappropriate, this RAM may be single-ported or multi-ported RAM. Thisdisclosure contemplates any suitable RAM. Memory 504 may include one ormore memories 504, where appropriate. Although this disclosure describesand illustrates particular memory, this disclosure contemplates anysuitable memory.

In particular embodiments, storage 506 includes mass storage for data orinstructions. As an example and not by way of limitation, storage 506may include a hard disk drive (HDD), a floppy disk drive, flash memory,an optical disc, a magneto-optical disc, magnetic tape, or a UniversalSerial Bus (USB) drive or a combination of two or more of these. Storage506 may include removable or non-removable (or fixed) media, whereappropriate. Storage 506 may be internal or external to computer system500, where appropriate. In particular embodiments, storage 506 isnon-volatile, solid-state memory. In particular embodiments, storage 506includes read-only memory (ROM). Where appropriate, this ROM may bemask-programmed ROM, programmable ROM (PROM), erasable PROM (EPROM),electrically erasable PROM (EEPROM), electrically alterable ROM (EAROM),or flash memory or a combination of two or more of these. Thisdisclosure contemplates mass storage 506 taking any suitable physicalform. Storage 506 may include one or more storage control unitsfacilitating communication between processor 502 and storage 506, whereappropriate. Where appropriate, storage 506 may include one or morestorages 506. Although this disclosure describes and illustratesparticular storage, this disclosure contemplates any suitable storage.

In particular embodiments, I/O interface 508 includes hardware,software, or both, providing one or more interfaces for communicationbetween computer system 500 and one or more I/O devices. Computer system500 may include one or more of these I/O devices, where appropriate. Oneor more of these I/O devices may enable communication between a personand computer system 500. As an example and not by way of limitation, anI/O device may include a keyboard, keypad, microphone, monitor, mouse,printer, scanner, speaker, still camera, stylus, tablet, touch screen,trackball, video camera, another suitable I/O device or a combination oftwo or more of these. An I/O device may include one or more sensors.This disclosure contemplates any suitable I/O devices and any suitableI/O interfaces 508 for them. Where appropriate, I/O interface 508 mayinclude one or more device or software drivers enabling processor 502 todrive one or more of these I/O devices. I/O interface 508 may includeone or more I/O interfaces 508, where appropriate. Although thisdisclosure describes and illustrates a particular I/O interface, thisdisclosure contemplates any suitable I/O interface.

In particular embodiments, communication interface 510 includeshardware, software, or both providing one or more interfaces forcommunication (such as, for example, packet-based communication) betweencomputer system 500 and one or more other computer systems 500 or one ormore networks. As an example and not by way of limitation, communicationinterface 510 may include a network interface controller (NIC) ornetwork adapter for communicating with an Ethernet or other wire-basednetwork or a wireless NIC (WNIC) or wireless adapter for communicatingwith a wireless network, such as a WI-FI network. This disclosurecontemplates any suitable network and any suitable communicationinterface 510 for it. As an example and not by way of limitation,computer system 500 may communicate with an ad hoc network, a personalarea network (PAN), a local area network (LAN), a wide area network(WAN), a metropolitan area network (MAN), or one or more portions of theInternet or a combination of two or more of these. One or more portionsof one or more of these networks may be wired or wireless. As anexample, computer system 500 may communicate with a wireless PAN (WPAN)(such as, for example, a BLUETOOTH WPAN), a WI-FI network, a WI-MAXnetwork, a cellular telephone network (such as, for example, a GlobalSystem for Mobile Communications (GSM) network), or other suitablewireless network or a combination of two or more of these. Computersystem 500 may include any suitable communication interface 510 for anyof these networks, where appropriate. Communication interface 510 mayinclude one or more communication interfaces 510, where appropriate.Although this disclosure describes and illustrates a particularcommunication interface, this disclosure contemplates any suitablecommunication interface.

In particular embodiments, bus 512 includes hardware, software, or bothcoupling components of computer system 500 to each other. As an exampleand not by way of limitation, bus 512 may include an AcceleratedGraphics Port (AGP) or other graphics bus, an Enhanced Industry StandardArchitecture (EISA) bus, a front-side bus (FSB), a HYPERTRANSPORT (HT)interconnect, an Industry Standard Architecture (ISA) bus, an INFINIBANDinterconnect, a low-pin-count (LPC) bus, a memory bus, a Micro ChannelArchitecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, aPCI-Express (PCIe) bus, a serial advanced technology attachment (SATA)bus, a Video Electronics Standards Association local (VLB) bus, oranother suitable bus or a combination of two or more of these. Bus 512may include one or more buses 512, where appropriate. Although thisdisclosure describes and illustrates a particular bus, this disclosurecontemplates any suitable bus or interconnect.

Herein, a computer-readable non-transitory storage medium or media mayinclude one or more semiconductor-based or other integrated circuits(ICs) (such, as for example, field-programmable gate arrays (FPGAs) orapplication-specific ICs (ASICs)), hard disk drives (HDDs), hybrid harddrives (HHDs), optical discs, optical disc drives (ODDs),magneto-optical discs, magneto-optical drives, floppy diskettes, floppydisk drives (FDDs), magnetic tapes, solid-state drives (SSDs),RAM-drives, SECURE DIGITAL cards or drives, any other suitablecomputer-readable non-transitory storage media, or any suitablecombination of two or more of these, where appropriate. Acomputer-readable non-transitory storage medium may be volatile,non-volatile, or a combination of volatile and non-volatile, whereappropriate.

Herein, “or” is inclusive and not exclusive, unless expressly indicatedotherwise or indicated otherwise by context. Therefore, herein, “A or B”means “A, B, or both,” unless expressly indicated otherwise or indicatedotherwise by context. Moreover, “and” is both joint and several, unlessexpressly indicated otherwise or indicated otherwise by context.Therefore, herein, “A and B” means “A and B, jointly or severally,”unless expressly indicated otherwise or indicated otherwise by context.

The scope of this disclosure encompasses all changes, substitutions,variations, alterations, and modifications to the example embodimentsdescribed or illustrated herein that a person having ordinary skill inthe art would comprehend. The scope of this disclosure is not limited tothe example embodiments described or illustrated herein. Moreover,although this disclosure describes and illustrates respectiveembodiments herein as including particular components, elements,feature, functions, operations, or steps, any of these embodiments mayinclude any combination or permutation of any of the components,elements, features, functions, operations, or steps described orillustrated anywhere herein that a person having ordinary skill in theart would comprehend. Furthermore, reference in the appended claims toan apparatus or system or a component of an apparatus or system beingadapted to, arranged to, capable of, configured to, enabled to, operableto, or operative to perform a particular function encompasses thatapparatus, system, component, whether or not it or that particularfunction is activated, turned on, or unlocked, as long as thatapparatus, system, or component is so adapted, arranged, capable,configured, enabled, operable, or operative.

What is claimed is:
 1. A method comprising: by one or more servercomputing devices, accessing a notification to be sent to a clientcomputing device, wherein the client computing device is one of aplurality of client computing devices associated with a user; by one ormore server computing devices, determining a current delivery context ofthe user; by one or more server computing devices, retrieving historicalnotification data associated with the user with respect to the currentdelivery context of the notification, wherein the historicalnotification data comprises conversion scores associated with one ormore available delivery channels to send the notification through,wherein a conversion score indicates a probability of the userinteracting with the notification, and wherein a delivery channelcomprises one or more uniquely-identified endpoint and one or morecommunication media; by one or more server computing devices, ranking,based on the conversion scores, the one or more delivery channels; byone or more server computing devices, determining a notification policyto apply to the notification based at least in part on the notification,the historical notification data, the conversion scores, or the currentdelivery context, wherein the notification policy specifies: to whichendpoint to send the notification to; or a communication medium to sendthe notification through; and by one or more server computing devices,applying the notification policy to the notification to be sent to theclient computing device.
 2. The method of claim 1, wherein the historyservice continuously updates the historical notification data based onreceived information from the client computing device about interactionsby the user with notifications sent to the user.
 3. The method of claim1, wherein the history service periodically: updates a model fordetermining conversion scores for notifications based on the historicalnotification data; and updates at least one notification policy based onthe updated model.
 4. The method of claim 3, wherein the model comprisesa decision-tree model, further comprising: determining, using thedecision-tree model, the conversion scores.
 5. The method of claim 1,wherein the determining the notification policy to apply to thenotification further comprises: retrieving, from a registration datastore, information about one or more communication media registered forthe user; or retrieving, from a registration data store, informationabout one or more endpoints registered for the user.
 6. The method ofclaim 5, wherein the determination of the notification policy to applyto the notification is further based on social-networking information ofthe user comprising: a relationship between the user and the source ofthe notification; or an affinity of the user for a user or entityassociated with the content of the notification.
 7. One or morecomputer-readable non-transitory storage media embodying software thatis operable when executed to: access a notification to be sent to aclient computing device, wherein the client computing device is one of aplurality of client computing devices associated with a user; determinea current delivery context of the user; retrieve historical notificationdata associated with the user with respect to the current deliverycontext of the notification, wherein the historical notification datacomprises conversion scores associated with one or more availabledelivery channels to send the notification through, wherein a conversionscore indicates a probability of the user interacting with thenotification, and wherein a delivery channel comprises one or moreuniquely-identified endpoint and one or more communication media; rank,based on the conversion scores, the one or more delivery channels;determine a notification policy to apply to the notification based atleast in part on the notification, the historical notification data, theconversion scores, or the current delivery context, wherein thenotification policy specifies: to which endpoint to send thenotification to; or a communication medium to send the notificationthrough; and apply the notification policy to the notification to besent to the client computing device.
 8. The media of claim 7, whereinthe history service continuously updates the historical notificationdata based on received information from the client computing deviceabout interactions by the user with notifications sent to the user. 9.The media of claim 7, wherein the history service periodically: updatesa model for determining conversion scores for notifications based on thehistorical notification data; and updates at least one notificationpolicy based on the updated model.
 10. The media of claim 9, wherein themodel comprises a decision-tree model, the software comprisinginstructions operable when executed to: determine, using thedecision-tree model, the conversion scores.
 11. The media of claim 7,wherein the instructions operable when executed to determine thenotification policy to apply to the notification further compriseinstructions operable when executed to: retrieve, from a registrationdata store, information about one or more communication media registeredfor the user; or retrieve, from a registration data store, informationabout one or more endpoints registered for the user.
 12. The media ofclaim 11, wherein the determination of the notification policy to applyto the notification is further based on social-networking information ofthe user comprising: a relationship between the user and the source ofthe notification; or an affinity of the user for a user or entityassociated with the content of the notification.
 13. A systemcomprising: one or more processors; and a memory coupled to theprocessors comprising instructions executable by the processors, theprocessors being operable when executing the instructions to: access anotification to be sent to a client computing device, wherein the clientcomputing device is one of a plurality of client computing devicesassociated with a user; determine a current delivery context of theuser; retrieve historical notification data associated with the userwith respect to the current delivery context of the notification,wherein the historical notification data comprises conversion scoresassociated with one or more available delivery channels to send thenotification through, wherein a conversion score indicates a probabilityof the user interacting with the notification, and wherein a deliverychannel comprises one or more uniquely-identified endpoint and one ormore communication media; rank, based on the conversion scores, the oneor more delivery channels; determine a notification policy to apply tothe notification based at least in part on the notification, thehistorical notification data, the conversion scores, or the currentdelivery context, wherein the notification policy specifies: to whichendpoint to send the notification to; or a communication medium to sendthe notification through; and apply the notification policy to thenotification to be sent to the client computing device.
 14. The systemof claim 13, wherein the history service continuously updates thehistorical notification data based on received information from theclient computing device about interactions by the user withnotifications sent to the user.
 15. The system of claim 13, wherein thehistory service periodically: updates a model for determining conversionscores for notifications based on the historical notification data; andupdates at least one notification policy based on the updated model. 16.The system of claim 15, wherein the model comprises a decision-treemodel, the software comprising instructions operable when executed to:determine, using the decision-tree model, the conversion scores.
 17. Thesystem of claim 13, wherein the instructions operable when executed todetermine the notification policy to apply to the notification furthercomprise instructions operable when executed to: retrieve, from aregistration data store, information about one or more communicationmedia registered for the user; or retrieve, from a registration datastore, information about one or more endpoints registered for the user.18. The system of claim 13, wherein the determination of thenotification policy to apply to the notification is further based onsocial-networking information of the user comprising: a relationshipbetween the user and the source of the notification; or an affinity ofthe user for a user or entity associated with the content of thenotification.